Method of separating components of pine oil



Patented June 5, 1934 PATENT OFFICE METHOD OF SEPARATING COMPONENTS OF IPINE OIL Lee T. Smith, Kenvil, N. J assignor to Hercules Powder Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationAugust 11, 1928, Serial No. 299,118

10 Claims.

My invention relates to an improved method of separating the componentsof pine oil and particularly those which when relatively purecrystallize at ordinary temperature, namely alpha terpineol, fenchylalcohol, borneol and anethol.

Pine oil, as is known, comprises various components namely,hydrocarbons, tertiary and sec ondary alcohols, ethers, ketones andaldehydes. In, for example, a high grade of steam distilled pine oil thetertiary alcohol, most of which is alpha-terpineol, amounts to fromabout to 70%. The secondary alcohols, namely borneol and fenchyl alcoholand the ether, anethol are minor constituents, the exact percentage,depending largely upon the amount of hydrocarbons present which normallyamounts to about 23-20%. The primarily most valuable components of pineoil are now the tertiary alcohol, alpha terpineol, the secondaryalcohols, borneol and fenchyl alcohol and the ether, anethol. Thesecomponents may be readily separated from the hydrocarbons bydistillation since the hydrocarbons boil below 190 C. as compared toboiling points of above 195 C. for the secondary and tertiary alcoholsand other components, which are only slightly soluble in thehydrocarbons. The secondary alcohols and the anethol are separated fromthe tertiary alcohols with substantial difiiculty and relativelyincompletely, in View of the fact that they are soluble in and havesimilar boiling points (200-23'7 C.) to those of the tertiary alcohols,.including alpha-terpineol, which boil at about 218 C. 1 i

The separation of the secondary alcohols, as borneol and ienchyl alcoholand of anethol from pine oil and from each other has been heretoforeeffected by, for example, the method disclosed in and forming thesubject matter of the application for patent of Irvin W. Humphrey,Serial No. 185,- 070, filed April 19, 1927, and which involves thetreatment of pine oil to effect the dehydration of the tertiary alcoholsfor the formation of water and hydrocarbons which may be readilyseparated from the secondary alcohols, along with the hydrocarbonsnormally components of the pine oil by distillation, after which thesecondary alcohols and the anethol may be separated from one another andfrom the remaining components of the pine oil by distillation. Suchprocess is highly advantageous but is open to objection when recovery ofthe alpha-terpineol is desirable, since, in the dehydration step, thealpha-terpineol is destroyed as such, being converted primarily intowater and the hydrocarbon dipentene.

Now in accordance with my invention, I so treat pine oil as to effectthe separation therefrom of the major portion of the alphaterpineol assuch, in crystalline form, then treat to effect conversion of anyremaining alpha-terpineol and other tertiary alcohols into water andhydrocarbons which are separated, by distillation, from the secondaryalcohols and the anethol, which are finally separated from each other bydistillation, Preferably, my invention involves initial fractionation ofpine oil into cuts in order to effect concentra- 651 tion of thetertiary alcohols and subjecting a cut or cuts rich in tertiary alcoholsto the treatment.

In the practical application of the method in accordance with myinvention, I'preferably sub- I ject pine oil to fractional distillationand collect a cut or cuts which contain relatively small amounts ofalpha-terpineol but which contain considerable amounts of, other,tertiary alcohols, boiling below alpha-terpineol, for example, a cutboiling within about the range 190 C.205 C.; 75. or cuts boiling withinabout the ranges 205 C.- 208 C, and 208 C.-214 C.; and a cut or cutsrich in alpha-terpineol, but containing only small proportions of othersubstances, for example, a cut boiling within about the range 214 C.218C., or cuts boiling within about the range 218 0.- 230 C. i

The cuts having been obtained, the cut, or cuts, rich in alpha-terpineolare refrigerated, for example, to 10 C., or refrigerated and seeded, forexample, with a crystal of alpha-terpineol, a grain of sand, or thelike, to eifect crystallization of the major portion of thealpha-terpineol, which is then separated by any convenient method, asby'decanting off the mother liquor or centrifuging.

The mother liquor, after the separation of the crystallizedalpha-terpineol, is then subjected to dehydration to effect the breakingdown of residual alpha-terpineol and any other tertiary ,alcoholspresent into water and hydrocarbons.

The dehydration is effected through heating with a dehydrating agent asfullers earth, or other argillaceous earth, iodine, bromine, siliceousearth, such as kieselguhr, activated carbon, etc., which willselectively attack the tertiary alcohols and not affect the secondaryalcohols or the anethol. The out, or cuts, containing only a smallamount of alpha-terpineol and considerable amounts of other tertiaryalcohols are subjected 0 to dehydration as in the case of the motherliquor remaining after removal of the crystallized alpha-terpineol, andsuch cut, or cuts, may be subjected to dehydration separately or theymay be rnlxed with the mother liquor, before .dehydration, and themixture subjected to dehydration.

After dehydration of the mother liquor remaining after the removal ofthe crystallized alphaterpineol and of the cut, or cuts, containing onlysmall amounts of alpha-terpineol, whether they be dehydrated separatelyor in admixture, the hydrocarbons resulting from the breaking down ofthe residual alpha-terpineol and other tertiary alcohols, and which boilat about 190 C. (about 170 C.-190 C.), are distilled off and finally thesecondary alcohols, as borneol (boilingv point about 212 C.) and fenchylalcohol (boiling point about 201 C.) and the anethol (boiling pointabout 234 C.), are separatelyrecovered by fractional distillation of theresidue and refrigeration, or refrigerating and seeding, of the cuts obtained.

As a more specific example of the practical application of my invention,for example, pine oil is fractionated and fractions, or cuts, separatelycollected. The fractions, or cuts, may have the boiling ranges as shownin the following table:

No. 1. Boiling below 190 C. No. 2. 190 C.205 C.

No. 3. 205 C.208 C.

No. 4. 208 C.-214 C. No.5, 214 C.218 C.

No. 6. Boiling over 218 C.

The out No. 1 boiling below 190 (3., comprising principallyhydrocarbons, is set aside. The out No. 5, in which alpha-terpineol isconcentrated, is refrigerated, for example to -10 C(Qlld. seeded toeffect the crystallization of the major portion of the alpha terpineolcontained therein, the crystallized alpha-terpineol being separated bycentrifugation.

The cuts Nos. 2, 3, 4 and 6 and the mother liquor, resulting from thecrystallization of alpha-terpineol from out No. 5, are then subjected todehydration, separately, for example, by adding to them about l-5% offullers earth and heating to a temperature of about 150 C., for a periodof 2-8 hours, or by adding .05-5% of iodine and heating to a temperatureof about 180 C., for about 16 hours. As a result of the dehydrationtreatment any residual alpha-terpineol in the mother liquor and tertiaryalcohols in cuts Nos. 2, 3, 4 and 6 will be broken down into water andhydrocarbons which "boil below 190 C. and which are readily fractionatedfrom the respective dehydrated cuts, leaving residues containing fenchylalcohol, borneol,'or anethol which may be readily separated'fromtheresidues by fractional distillation thereof followed by refrigeration or refrigeration and seeding, or where the cuts are sufficientlyrich, by refrigeration and seeding without prior distillation.

If desired, the cuts Nos. 2, 3, 4 and 6 may be mixed with each other andwith the mother liquor before dehydration, but with such procedure thesecondary alcohols and the anethol will be all in one residue ratherthan in separate residues and hence separate recovery will involvesomewhat greater care in fractionating.

As a further example of the practical adaptation of the method accordingto myinvention, pine oil is fractionated into cuts No. 1 boiling below214 C. and No. 2 boiling between 214 C.- 218 C., a residue being left.From out No. 2, after refrigeration to say about -10 C. and seeding, alarge amount of alpha-terpineol will separate out in crystalline form.The mother liquor resulting from the crystallization of alpha-terpineolis added to out No. 1, the residue is added and the mixture subjected todehydration, for example, through heating to say 'a temperature of about150 C. with about 1-5% of fullers earth for about 2-8 hours, or to atemperature of say about 180 C. with about 0.05-5% of iodine for about1-6 hours. The dehydrated mixture is distilled to separate off thehydrocarbons and water boiling below 190 C. The residue is fractionallydistilled and pure fenchyl alcohol, b. p. 201 C., borneol, b. p. 212 C.,and anethol, b. p. 234 C. separated by crystallization fromthe severaldlstillates, or cuts obtained, as by refrigeration, or refrigeration andseeding.

The amount ofrecovery, or separation, of the desirable constituents ofthe pine oil according to the method of my invention will dependsomewhat upon the efliciency of the initial fractionation and the amountand character of the dehydrating agent, it being desirable to avoid theformation of any considerable amount of highboiling polymerizedhydrocarbonswhich will effect destruction of a part of the desiredproducts and which will tend to retain borneol, fenchyl alcohol andanethol in solution preventing their crystallization.

It will be understood that where in the claims appended hereto referenceis made to pine oil, I intend to include by the term pine oil, a cut, orcuts, obtained by the fractional distillation of pine oil.

Having now fully described my invention, What I claim and desire toprotect by Letters Patent is:

1. The method of separating fenchyl alcohol, borneol and anethol frompine oil which includes fractionating pine oil to obtain a cut boilingWithin about the range 214 C.-2l8 C. and rich in alpha-terpineol andcuts boiling within about the range 195 C.-240 C. and containingtertiary alcohols, refrigerating the cut rich in alpha-terpineol toeffect crystallization of alpha-terpineol therefrom, separating thecrystallized alpha-terpineol from said out, treating the several cutswith a dehydrating agent to effect the conversion of tertiary alcoholscontained therein into hydrocarbons and water, fractionating the cuts ata temperature within about the range 170 C.- 190 C. for the separationtherefrom of hydrocarbons, fractionating the residues to obtain cutsboiling within about the range 195 C.-205 C.

and rich in fenchyl alcohol, 208 C.-214 C. and

rich in borneol, and 225 C.-244 C. and rich in anethol and effecting thecrystallization of fenchyl alcohol, borneol and anethol from the cutsrespectively. Y i

2. The method "of separating asecondary alcohol from'pine oil whichincludes separatinga tertiary alcohol in crystalline form from the pineoil, converting residual tertiary alcohols in the residue tohydrocarbons and water, fractionating oif the hydrocarbons andseparating a secondary alcohol from the residue. i

3. The method of separating secondary alcohols from pine oil whichincludes separating a tertiary alcohol in crystalline form therefrom,

subjecting the residue to dehydration to effect conversion ofresidualtertiary alcohols in the residue to hydrocarbons. and water,fractionating the residue into cuts rich in the secondary alcoholsrespectively and effecting crystallization of the secondary alcoholsfrom the cuts respectively.

4. The method of separating pine oil into its individual constituentswhich includes separating alpha-terpineol in crystalline form from thepine oil, subjecting the residue to dehydration to effect the conversionof tertiary alcoholscontained ftherein into hydrocarbons and water,fractionating off hydrocarbons, fractionating the residue to obtain cutsrich in the individual constituents of the residue and separating theseveral constituents from the several cuts respectively.

5. The method of separating pine oil into its individual constituentswhich includes separating alpha-terpineol in crystalline form from thepine oil, subjecting the residue to dehydration to effect the conversionof tertiary alcohols contained therein into hydrocarbons and water,fractionating ofi hydrocarbons, fractionating the residue to obtain cutsrich in the individual constituents of the residue and crystallizing theseveral constituents from the several cuts respectively.

6. The method of separating secondary alcohols from pine oil whichincludes fractionating pine oil to obtain a plurality of cuts, one ofwhich contains the major part of the alpha-terpineol content of the pineoil, crystallizing alpha-terpineol from the cut containing the majorpartof the alpha-terpineol content of the pine oil, separatingcrystalline alpha-terpineol, mixing the cuts, dehydrating the mixed cutsto convert tertiary alcohols contained therein to hydrocarbons andwater, fractionating off hydrocarbons, fractionating the residue intofractions rich in secondary alcohols and crystallizing a secondaryalcohol from the several cuts respectively.

7. The method of separating fenchyl alcohol, borneol and anethol frompine oil which includes fractionating pine oil to obtain a plurality ofcuts, one of which contains the major part of the alpha-terpineolcontent of the pine oil, crystallizing alpha-terpineol from the cutcontaining the major part of the alpha-terpineol content of the pineoil, separating crystalline alpha-terpineol, mixing the cuts,dehydrating the mixed cuts to convert-tertiary alcohols containedtherein to hydrocarbons and water, iractionating off hydrocarbons,fractionating the residue into fractions rich in fenchyl alcohol,borneol and anethol and crystallizing fenchyl alcohol, borneol andanethol from the several cuts respectively.

8. The method of separating borneol from pine oil which includesseparating a tertiary alcohol in crystalline form from pine oil,converting residual tertiary alcohols in the remaining pine oil intohydrocarbons and water, fractionating off the hydrocarbons,fractionating the residue to obtain a cut rich in borneol and separatingthe borneol from said out.

9. The method of separating borneol from pine oil which includesfractionating the pine oil to obtain a cut rich in alpha-terpineol,crystallizing mother liquor for the conversion of residual tertiaryalcohols to hydrocarbons and water, fractionating off hydrocarbons,fractionating the residue to obtain a cut rich in borneol and effectingcrystallization of borneol from said out.

10. The method of separating borneol from pine oil which includesseparating alpha-terpineol in crystalline form from the pine oil,converting c5 alpha-terpineol from said out, dehydrating the.

tertiary alcohols remaining in the pine oil to hydrocarbons and water,fractionating oii hydro carbons and water, fractionating the residue toobtain a cut rich in borneol and crystallizing borneol from said out.

LEE T. SMITH.

